The present invention relates to a specific medical device known as a rongeur, and more particularly to a rongeur and a method of cleaning a rongeur between uses.
The rongeur is a medical instrument utilized for a variety of specific tasks. It is particularly useful for removing small amounts of bone, although it is sometimes utilized to remove cartilage or other body material from such places as the knee, cervix, and vertebrae in the back, to name a few specific applications.
A rongeur normally has a long fixed shank with an anvil or a footplate at its distal end and a handle at its proximal end. A reciprocating shaft or crossbar moves substantially axially with respect to the fixed shank, either inside a hollow fixed shank or along the outside surface of a rigid fixed shank. An abutment forming a cutter on the distal end of the reciprocating crossbar abuts the footplate to cut tissue captured between the cutter and the footplate. The proximal end of the crossbar is attached to a trigger mechanism for the reciprocating of the crossbar to move the cutter against the footplate.
A traditional trigger mechanism is often utilized having a grip which is received along the palm of a user. The grip is usually not moveable with respect to the rigid fixed shaft. A lever rotates about a first pivot relative to the grip, with a first portion of the lever grasped by a user. A second portion of the lever is located between the first pivot and a second pivot which connects with the crossbar. A spring mechanism separates the first portion of the lever from the grip. Similar structures may be seen in U.S. Pat. Nos. 5,312,407 and 5,061,269.
To operate the trigger mechanism, a user grasps the trigger and squeezes the first portion toward the grip to overcome the bias of the spring mechanism. The first portion pivots toward the grip and the second portion rotates about the first pivot. As this occurs, the second pivot along with the crossbar are moved along the rigid fixed shaft until the cutter contacts the foot plate.
In most ronjeur designs, as the second portion of the lever rotates about the first pivot, it follows a circular path. This causes a portion of the crossbar, including the second pivot, near the proximal end of the rigid fixed shaft to move upwardly away from the rigid fixed shaft initially during the operation of the trigger mechanism. At a point during the operation process, a line through the first and second pivots would be perpendicular to the rigid fixed member and the second pivot will begin to move back towards the rigid fixed shaft as it moves the second pivot towards the distal end and the cutter towards the foot plate. Once the cutter contacts the footplate and applies a force, the crossbar may once again be contacting the rigid fixed shaft near the second pivot.
When the first portion of the lever is released, the spring mechanism applies a force to separate the first portion of the lever from the grip to draw the crossbar in the proximal direction. When the crossbar contacts the rigid fixed shaft near the second pivot, proximal, or rearward motion of the crossbar stops thereby leaving a space between the cutter and the footplate. This is a ready position for the rongeur.
While the movement of the crossbar at the second pivot upwardly and downwardly does not affect the ability of the cutter to operate with the footplate to a significant degree, it does create a gap during operation which allows for tissue, debris or body fluids including blood to enter the gap during operation.
Since the resting position of the rongeur is with the rigid fixed member in contact with the crossbar along their interfacing surfaces, any entrapped debris or solution between the interfacing surfaces may not be removed during the cleaning process. Accordingly, although a rongeur may be steam cleaned, since the entrapped waste is located between interfacing surfaces, it is not easily removed during the cleaning process.
Failure to remove entrapped waste could result in a build up resulting in the operation of the rongeur to be xe2x80x9cstickyxe2x80x9d. This creates problems for the surgeon as well as for the surgical equipment manufacturer. A specific feel is anticipated by the surgeon during each use of the rongeur. Additionally, health risks may result to a subsequent patient since bacteria could cultivate on waste products. This poses a number of problems for the patient as well as the medical community.
A number of rongeurs and techniques have been developed to attempt to solve the problem of eliminating waste from interfacing surfaces of rongeurs. Some rongeurs are disassembled during the cleaning process. While this is a very good way of cleaning a rongeur, the re-assembly of the rongeur is sometimes challenging for personnel. Furthermore, if parts are inadvertently lost during the cleaning process, the rongeur will not operate properly. U.S. Pat. No. 5,961,531 describes various other problems with disassembling rongeurs for cleaning purposes and describes a xe2x80x9cconvertiblexe2x80x9d rongeur, apparently one which allows the crossbar to be lifted away from the rigid fixed shaft without requiring detachment, or removal, of any parts.
While U.S. Pat. No. 5,961,531 provides one way of addressing the problem of cleaning between the crossbar and the rigid fixed member, it creates a new level of complexity in the construction of a rongeur. A need still exists for a simpler, and less complicated rongeur and method of cleaning a rongeur while still preserving the utility of prior art rongeurs.
Consequently, it is an object of the present invention to provide a rongeur and a method of cleaning a rongeur that permits thorough cleaning without disassembly of the rongeur.
It is another object of the present invention to provide a rongeur which is not partially disassembled during the cleaning process.
Another object of the present invention is to provide a method for cleaning a rongeur which adequately removes entrapped waste between the crossbar and the rigid fixed shaft.
Accordingly, the present invention provides a rongeur with a crossbar which moves relative to a rigid fixed shaft having a footplate at a distal end. A distal end of the crossbar operates as a cutter with footplate of the rigid fixed shaft. The crossbar is operably coupled to an actuator proximal to the distal end. The actuator pivots about a first pivot.
The first pivot separates the lever into a first and a second portion. As the lever is operated to move the crossbar so that the cutter contacts the footplate, the second portion, or actuator, moves along a circular path about the first pivot. This lifts the crossbar away from the rigid fixed shaft where the crossbar is operated by the second portion of the lever to create a gap. Once the operating point and the first pivot are aligned perpendicularly to the rigid fixed shaft, the second portion then directs the operating point towards the rigid fixed member along the circular path as the cutter nears the footplate to close the gap between the crossbar and the rigid fixed shaft at the operating point. While similar structure is utilized in the prior art, no one is believed to have undertaken efforts to clean the rongeur while maintaining a gap between the crossbar and the rigid fixed.
Accordingly a releasable, removable, and preferably a disposable retainer is utilized to maintain the gap between the crossbar and the rigid fixed shaft during the cleaning operation by positioning the retainer to partially operate the crossbar between the ready and the cutting position with the gap being maintained between the crossbar and the rigid fixed shaft. The retainer may take the form of a disposable O-ring which overcomes at least some of the bias of the spring member which normally would maintain the rongeur in a ready position.